DECADE L. Chen
Internet-Draft H. Liu
Intended status: Informational Yale University
Expires: April 21, 2011 October 18, 2010
Leveraging In-network Storage in P2P LiveStreaming
draft-chen-decade-intgr-livestr-exmp-00
Abstract
DECADE is an in-network storage infrastructure under discussions and
constructions. It can be integrated into Peer-to-Peer (P2P)
applications to achieve more efficient content distributions. This
document represents a detailed example of integrating DECADE with a
dominating P2P application - P2P livestreaming. This document
describes a preliminary framework of DECADE client API, P2P live
streaming integration, the environment of the test on this
integrarion and application performance analysis in the test.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Concepts . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
2.1. DECADE Server . . . . . . . . . . . . . . . . . . . . . . . 3
2.2. DECADE Client Plug-in . . . . . . . . . . . . . . . . . . . 3
2.3. P2P LiveStreaming Client . . . . . . . . . . . . . . . . . 4
3. DECADE Client API . . . . . . . . . . . . . . . . . . . . . . . 4
4. DECADE Integration of P2P LiveStreaming Client . . . . . . . . 4
4.1. DECADE Client Plug-in . . . . . . . . . . . . . . . . . . . 5
4.2. DECADE Integration Architecture . . . . . . . . . . . . . . 5
4.2.1. Data Access . . . . . . . . . . . . . . . . . . . . . . 5
4.2.2. Message Control . . . . . . . . . . . . . . . . . . . . 6
5. Test Environment and Settings . . . . . . . . . . . . . . . . . 6
5.1. Test Settings . . . . . . . . . . . . . . . . . . . . . . . 6
5.2. Platforms and Components . . . . . . . . . . . . . . . . . 6
5.2.1. EC2 DECADE Server . . . . . . . . . . . . . . . . . . . 7
5.2.2. PlanetLab P2P LiveStreaming Client . . . . . . . . . . 7
5.2.3. Tracker . . . . . . . . . . . . . . . . . . . . . . . . 7
5.2.4. Source Server . . . . . . . . . . . . . . . . . . . . . 7
5.2.5. Test Controller . . . . . . . . . . . . . . . . . . . . 8
6. Performance Analysis . . . . . . . . . . . . . . . . . . . . . 8
6.1. Performance Metrics . . . . . . . . . . . . . . . . . . . . 8
6.2. Result and Analysis . . . . . . . . . . . . . . . . . . . . 8
7. Security Considerations . . . . . . . . . . . . . . . . . . . . 9
8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 9
9. Normative References . . . . . . . . . . . . . . . . . . . . . 9
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 9
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1. Introduction
DECADE is an in-network storage infrastructure under discussions and
constructions. It can be integrated into Peer-to-Peer (P2P)
applications to achieve more efficient content distributions.
This draft introduces an instance of application integration with
DECADE. In our example system, the core component includes DECADE
server and DECADE-aware P2P live stream client. DECADE server
running at Linux platform is designed to support data reading and
writing for DECADE clients. For DECADE client, we employed a P2P
live streaming system called P2PLS (P2P Live Streaming). We utilized
a preliminary API (Application Programming Interface) set provided by
DECADE to enable P2PLS clients to leverage DECADE in their data
transmission. In this draft, we introduce the system structure of
the DECADE-P2PLS integration system, the main DECADE related message
flow, the environment of the test on this integration, and the system
performance in the test.
Please note that P2PLS in this draft only represents the usage case
of "live streaming" out of a large number of P2P applications, while
DECADE itself can support other applications. The API set of DECADE
is only an experimental design and implementation. It is not a
standard and is still under development.
2. Concepts
2.1. DECADE Server
DECADE Server is a server implemented DECADE protocols, management
mechanism and storage strategies. It is an important element to
provide DECADE services. In a DECADE server, we have a number of
Data Lockers which are virtual accounts and storage space for
applications.
2.2. DECADE Client Plug-in
DECADE Client Plug-in is a plug-in component for application clients
to use DECADE server. This plug-in component is served as an
application-specific interface between a particular application and
DECADE servers. It can be a very simple component of basic DECADE
access APIs implemented, or a smart component to integrate
application-specific control strategies with DECADE APIs.
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2.3. P2P LiveStreaming Client
P2P LiveStreaming Client is our self-maintained version of a native
P2P live streaming application.
3. DECADE Client API
In order to simplify the usage of DECADE server for P2P application
clients, we provide a set of APIs. On top of these APIs, a P2P
application client can develop its application-specific control and
data distributed policies to utilize DECADE servers.
There are five basic APIs:
o Get_Object: to get an object from a DECADE server with an
authorized token. The get operation can be classified into two
categories: Local Get and Remote Get. Local Get is to get an
object from a local DECADE server. Remote Get is to use an
application's local DECADE server to indirectly get an object from
a remote DECADE server. The object will first passed to the local
DECADE server, then return to the application client
o Put_Object: to store an object into a DECADE server with an
authorized token. An application client can either store an
object in its local DECADE server or in other clients' DECADE
servers, if it has a authorized token. Both operates are directly
store, we don't provide indirectly store (i.e. remote put).
o Delete_Object: to delete an object in a DECADE server explicitly
with an authorized token. Know that an object can be deleted
implicitly by setting a expired time or a specific TTL.
o Status_Query: to query current status of an application itself,
including a list of stored objects, resource usage, and so on. An
application cannot query others' status.
o Generate_Token: to generate an authorized token. The token can be
used to access an application client's local DECADE server, or
passed to other clients to allow others to access its DECADE
server.
4. DECADE Integration of P2P LiveStreaming Client
We integrate DECADE client API with a P2P live streaming application,
in order that clients of this P2P live streaming application can
easily utilize DECADE server in their data transport processes.
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4.1. DECADE Client Plug-in
DECADE Client Plug-in is a plug-in component, on top of DECADE client
APIs, designed for application clients to use DECADE server. This
plug-in component serves as an application-specific interface between
a particular application and DECADE servers. In this test, we
employed P2P live streaming application to leverage this plug -in.
4.2. DECADE Integration Architecture
The architecture of the P2P live streaming and DECADE integration is
in Figure 1:
+---------------+ +---------------+
| DECADE | | DECADE |
| Peer | | Peer |
|+-------------+| +---------------+ |+-------------+|
||DECADE Client |---| DECADE Server |---||DECADE Client||
|+------^------+| +---------------+ |+------^------+|
| API | | | API | |
|+------v------+| +---------------+ |+------v------+|
||Native Client||---| Tracker |---||Native Client||
|+-------------+| +---------------+ |+-------------+|
+---------------+ +---------------+
Figure 1
A DECADE integrated P2P live streaming client uses DECADE client
plug-in to communicate with its DECADE server and access data between
itself and DECADE servers. It uses an additional modified message
protocol, as well as its original P2P message protocols to connect
with other peers, exchange control messages.
4.2.1. Data Access
DECADE client plug-in is called whenever the application want to get
data objects from (or put data objects into) DECADE servers. Every
data object transferred between DECADE server and original P2P live
streaming client must go through this plug-in. Neither the DECADE
server and the original client knows each other. A Data object is a
transfer unit of data, between DECADE servers and application
clients. It the size of data object can be application-customized,
according to variable requirements of performance or sensitive
factors (e.g. low latency, high bandwidth utilization).
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4.2.2. Message Control
Control and Data plane decoupling is a design principle of DECADE.
Control messages are propagated in an original P2P way. Besides,
original P2P control messages, a modified message protocol is needed
for DECADE authorized token delivery. By exchanging DECADE
authorized tokens, P2P live streaming clients can retrieve or store
data objects into or from other clients' DECADE servers.
5. Test Environment and Settings
In order to demo our DECADE integrated P2P live streaming
application, we conduct an test in Amazon EC2 and PlanetLab to show
the performance of the system. For comparison, we conduct two tests,
DECADE integrated P2P live streaming and native P2P live streaming,
in the same environment use the same setting.
5.1. Test Settings
Our test ran on a wide-spread area and a diverse platforms,including
a famous commercial cloud platform and a well-known testbed
PlanetLab. The environment settings are as following:
o EC2 Regions: we setup DECADE servers in Amazon EC2 cloud,
including all four regions around the world, US east, US west,
Europe and Asia.
o PlanetLab: we run our P2P live streaming clients (both DECADE
integrated and native clients) on PlanetLab of a wild-spread area.
o Arrival pattern: we let all the clients join at the same time to
simulate a flash crown scenario.
o Total Bandwidth: for fair comparison, we set the system's total
supply bandwidth to be exact the same in both test.
5.2. Platforms and Components
In our test, we have different functional components running in
different platforms, including DECADE servers, P2P live streaming
clients(DECADE integrated or Native), Tracker, Source server and Test
Controller, as shown in Figure 2.
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+----------+ +------------+ +------------+
| P2PLS | /| DECADE |----| DECADE |
| Manager | / | Server | | Server |
+--------^\+ / +-----|------+ +------|-----+ EC2
___________\/_________|__________________|_______
/\ | |
+---------/+ \ +-----|------+ +------|-----+
| P2PLS ^ \ | P2PLS ^ ^ P2PLS |
| Source |\ \| Client |\ /| Client |
+-----|----+ \ \------^-----+ \/ +------^-----+ Planetlab
______|_______\__\_____|_______/\________|_______
| \ \ | / \ |
+-----|----+ v--v---v-----v v------v-----+
| Streaming| | P2PLS | | Test |
| Files | | Tracker | | Controller |
+----------+ +------------+ +------------+ Yale Lab
P2PLS represents to P2P LiveStreaming.
Figure 2
5.2.1. EC2 DECADE Server
DECADE Servers ran on Amazon EC2 small instances, with bandwidth
constraint.
5.2.2. PlanetLab P2P LiveStreaming Client
Both DECADE integrated and Native P2P live streaming clients run in
planetlab spreading in different locations in the world. The DECADE
integrated P2P live streaming clients connect to a closest DECADE
server according to its Geo-location distance of the servers. DECADE
integrated P2P live streaming clients use their DECADE servers to
upload to neighbors, instead of their own "last-mile" bandwidth.
5.2.3. Tracker
A native P2P live streaming tracker ran in our lab to serve for both
DECADE integrated clients and native clients during the test.
5.2.4. Source Server
A native P2P live streaming source server ran in our lab to serve for
both DECADE integrated clients and native clients during the test.
The capacity of source is equivalently constrain for both cases.
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5.2.5. Test Controller
Test Controller is a manager to control all machines behaviors in
both EC2 and PlanetLab during the test.
6. Performance Analysis
During the test, DECADE integrated P2P live streaming clients achieve
a better performance in the results.
6.1. Performance Metrics
o Startup Delay: the time from a peer joins the channel to the
moment it starts to play.
o Piece Missed Rate: number of pieces a peer missed in the playing
buffer to total number of pieces.
o Freeze Times: number of a peer freeze during playing.
o Average Peer Uploading Rate: Average uploading bandwidth of a peer
per second.
6.2. Result and Analysis
o Startup Delay: In the test, DECADE integrated P2P live streaming
clients startup around 35~40 seconds. some of them startup at
about 10 seconds. Native P2P live streaming clients startup
around 110~120 seconds. less than 20% of them startup within 100
seconds.
o Piece Missed Rate: In the test, both DECADE integrated P2P live
streaming clients and native P2P live streaming clients achieved a
good performance in pieces missed rate. Only about 0.02% of total
pieces missed in both cases.
o Freeze Times: In the test, native P2P live streaming clients
suffered from 40% more freeze than DECADE Integrated P2P live
streaming clients.
o Average Peer Uploading Rate: In the test, according to our
settings, DECADE integrated P2P live streaming clients had no
upload in their "last-mile" access network. More than 70% of
peers uploaded much more than streaming rate. That is to say,
much uploading bandwidth are waste during data transport.
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7. Security Considerations
This document does not contain any security considerations.
8. IANA Considerations
This document does not have any IANA considerations.
9. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
Authors' Addresses
Lijiang Chen
Yale University
Email: lijiang.chen@yale.edu
Hongqiang Liu
Yale University
Email: hongqiang.liu@yale.edu
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